On May 6, 12:08*pm, "Michael A. Terrell"
wrote:
w_tom wrote:
On May 4, 9:09 pm, "Michael A. Terrell"
wrote:
* *The same thing we did in the studios and transmitter sites. *Use a
combination of protection at the building's main disconnect, and
individual protection at each critical device. *The only thing that I've
lost in the last ten years was when lightning hit a huge pine tree, and
cut the top half of it off. It landed on the ground right over the
buried telephone line, and a second strike blew out the modem and MOV
protection on the phone line.
* You suffered damage from a lightning strike and call that effective
protection? *Modems are most typically damaged by surges entering an
AC mains. *Outgoing surge path would be the phone line to earth via a
telco installed *'whole house' protector. *Damage from lightning is
effective protection? *After spending how much for all those
protectors, you call that protection?
* *Where did I say HOW was protected? It was my second week at that
station, and the chief engineer took off on a long overdue vacation. If
you would learn to read, rather than just do mindless rants you wouldn't
look so stupid. *At that time the building had a UFER ground, and a
three phase protection system at the meter CTs. That didn't prevent the
damage, as you claim it should.
* Phone lines do not use MOV protectors. *Basic information that you
would have learned if not wasting time insulting people.
* *Sorry, _wacko_ but you are the one slinging insults and ignoring
proof from hundreds of people.
*MOVs have
too much capacitance. *Phone line 'whole house' protectors use other
technologies with lower capacitance.
* *Gee, _wacko_ you've never seen ANY modern business telephone
equipment? *Gas tubes are fragile and very expensive. The protection
isn't to save the privately owned telephones, it it to limit damage to
the building. *Even that mid '60s 1A2 system had every output of the
power supply fused to prevent a fire. Explain why an MOV's capacitance
is high enough to affect a phone line. Never mind. *I have a Nitsuko/NEC
DX2NA-32SYTEMEM KEY TELEPHONE SYSTEM in front of me, and every CO line
in it has a MOV across the line. *Once more, you're preaching lies and
using deceit to try to make others look bad.
,http://refurbishednitsuko.net/productInfo.aspx?productID=75978489-9ac....
is the Central Office line card for four telephone lines. See the black
MOVs to the right of each pair of fuses?
http://refurbishednitsuko.net/productInfo.aspx?productID=f5453e33-047....
is the card for four standard 2500 type telephones, or equivalent
equipment. See the pairs of black MOVs over the blue connectors at the
bottom of the screen? They are all japanese, with no brand markings.
http://www.epcos.com/web/generator/Web/Sections/Publications/PDF/SIOV...
is the Epcos MOV databook, with datasheets for Telecom applications.
page 213 list the TELECOM MOV data.
* *Every line into that studio building had a long distance call device
diverter in the line that had MOV across the phone line. Every one of
them survived the direct hit to the building and STL tower. That's more
than can be said of your ability to use reason, and learn new things.
* *You need to get your head out of 1920 and learn modern electronics.
The one thing we learned today is that you don't know any more about
Telecom that you do lightning protection, or reading comprehension.
W_ denies MOVs are commonly used in typical electonics or modern
appliances too. He had to, because he can't answer the obvious
question of how MOVs can be used effectively in these applications,
yet they can't work in plug-in protectors and the only way to get any
protection is to have a nearby direct earth ground. Faced with the
problem of MOVs providing protection in electronics/appliance without
an earthground, he simply denies MOVs are used in electronics and
appliances. Here's the references that I provvided him on that one:
Here, from Appliance Magazine and Appliance Design websites:
http://www.appliancedesign.com/CDA/A.../BNP_GUID_9-5-...
"New thermally enhanced MOVs help protect a wide variety of low-power
systems against damage caused by over-current, over-temperature and
over-voltage faults, including lightning strikes, electrostatic
discharge (ESD) surges, loss of neutral, incorrect input voltage and
power induction.
These devices help provide protection in a wide range of AC line
applications, including AC mains LED lighting systems, PLC network
adapters, cell-phone chargers, AC/DC power supplies (up to 30 VA as
input power for 230 VAC input voltage), modem power supplies, AC
panel
protection modules, AC power meters, and home appliances. "
http://www.appliancemagazine.com/pri...zone=1&first=1
"Protecting increasingly sophisticated and complex control boards
from
misconnection, power surges, or short circuit damage is of particular
concern to the equipment manufacturer. Although appliance
transformers, their enclosures, and connections are capable of
withstanding higher voltage transients, the use of sensitive solid-
state devices on the board necessitates improved overcurrent,
overtemperature, and overvoltage control.
Coordinating overcurrent and overvoltage protection can also help
designers comply with safety agency requirements, minimize component
count, and improve equipment reliability. A metal oxide varistor
(MOV)
overvoltage protection device used in a coordinated circuit-
protection
strategy with a line-voltage-rated PPTC overcurrent device helps
manufacturers meet IEC 6100-4-5, the global standard for voltage and
current test conditions for equipment connected to ac mains."